Bamboo Framework System

ABSTRACT

A bamboo framework used to transfer load and attach face panels for a building. The framework consists of spaced bamboo culms, flexible inner rings that wrap around the bamboo culms, middle connectors to attach face panels, end connectors to attach face panels and transfer load from framework to support structures, and three types of additional metal connectors to strengthen the framework.

CROSS-REFERENCE TO RELATED APPLICATIONS

U.S. Pat. No. 606,623, Jun. 28, 1898, by Durant; W. N. and Prichard; W. H.

U.S. Pat. No. 3,297,063, Jan. 10, 1967, by McGuire; J. C.

U.S. Pat. No. D366120, Jan. 9, 1996, by Atkinson; R. R.

U.S. Pat. No. 5,916,105, Jun. 29, 1999, by Gow; R. H.

U.S. Pat. No. 6,447,198, Sep. 10, 2002, by Schmidmeier; A.

U.S. Pat. No. 6,576,331, Jun. 10, 2003, by Ryan; D. B.

U.S. Pat. No. 6,957,479, Oct. 25, 2005, by Londono; J. B., Cheyne; D.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to a framework consisting of bamboo culms. The framework can be used to support both structural load of a building and attach face panels.

2. Prior Art

Bamboo has been used as a building material in various ways, such as bamboo floors, panels made of bamboo fibers, ceilings, etc. In Asia and South America, bamboo is also used for structural support of a building. For this purpose, the culms of bamboos have a large diameter that may range from three to seven inches. Bamboo has many environmentally friendly features, comparing to other commonly used building materials such as wood, concrete, brick, and steel. It grows fast and can be harvested in less than ten years. As a natural material, it does not generate harmful emissions. It is also very light, which does not only facilitate transportation, but also reduces the total weight of a building.

However, there are several challenges that impede the use of bamboo culms as a structural material. Because bamboo culms split lengthwise very easily if they are joined by nailing, the connection between them or with other building materials is difficult. For many years, different connections have been tried. Bamboo culms are connected by intricate pin systems that use no other materials other than bamboos themselves. They are connected by lashing systems based on tying. U.S. Pat. No. 6,957,479 “Method for Preparing a Terminal Assembly for Bamboo”, issued to Londono; J. B. and Cheyne; D, describes a method to prepare a terminal assembly for bamboo culms to facilitate connection.

German Patent DE 3817236 “Junction Connection for Frameworks consisting of Bamboo”, issued to Brusnowitz Gierg Dipling, describes a connection system for three-dimensional structures. These methods are labor intensive and time consuming. Another challenge is the poor fire resistance of bamboo culms. In addition, bamboo culms deteriorate rapidly if they are frequently contacted with water. In a modern building, building frames are well covered for aesthetics, protection against fire and moisture damage, and accommodation of electrical conduits and mechanical pipes. The existing bamboo structural systems do not adequately address the connection problems such that different building materials can be seamlessly integrated to create a building comparable with those supported by wood, concrete, masonry, and steel.

The present invention deals with connections between bamboo culms, between bamboo culms and other structural components, and between bamboo culms and panels used for sheathing, subflooring, and drywalls. In accordance with the present, direct contact between bamboo culms is not necessary. The invention has a wide range of applications including, but not limited to, load bearing walls, non-load bearing partition walls, and floors.

BACKGROUND OF THE INVENTION—OBJECTS AND ADVANTAGES

The invention provides a framework that uses bamboo culms as the structural material. Different connections are incorporated in the invention to transfer structural load and to integrate with other building materials. The objects and advantages of the present invention are:

-   -   (a) to transfer structural load effectively from floor or wall         panels to bamboo frames;     -   (b) to transfer structural load effectively from bamboo frames         to other structural components;     -   (c) to distribute load uniformly among individual bamboo culms;     -   (d) to protect the bamboo frames from fire and moisture damage;     -   (e) to conceal the bamboo frames for aesthetics;     -   (f) to provide spaces for accommodating electrical conduits and         mechanical pipes in a building;     -   (g) to facilitate the use of bamboo, which is not only         environmentally friendly, but also reduces building cost.

Still further objects and advantages will become apparent from a consideration of the following description and drawings.

SUMMARY

In accordance with the present invention a framework comprises bamboo frames, rings made of flexible materials, middle connectors, end connectors, metal straps, diagonal metal connectors, and channel metal connectors, bolts, washers, nuts, and screws.

In the drawings, closely related figures have the same number but different alphabetic suffixes.

DRAWINGS—FIGURES

FIG. 1 shows the application of a portion of the framework in a wall or a floor.

FIG. 2 shows section A-A of the portion of the framework in FIG. 1.

FIG. 3A shows section B-B of the portion of the framework in FIG. 1.

FIG. 3B shows the details of the section at the second bamboo culm in FIG. 3A.

FIG. 4A shows the middle connector.

FIG. 4B shows the flexible inner ring.

FIG. 4C shows the end connector.

FIG. 4D shows the channel metal connector.

FIG. 4E shows the diagonal metal connector.

FIG. 4F shows the metal strap connector.

DRAWINGS—REFERENCE NUMERALS

10 bamboo culm 12 middle connector 14 flexible inner ring 16 end connector 18 metal strap connector 20 channel metal connector 22 diagonal metal connector 24 bolt 26 structural support of the framework 28 face panel 30 screw

DETAILED DESCRIPTION—FIGS. 1, 2, 3, AND 4—PREFERRED EMBODIMENT

A preferred embodiment of the present invention is illustrated in FIGS. 1, 2, 3, and 4.

The framework consists of structural bamboo culms 10, cut at the same length and spaced equally. When selecting bamboo culms, it is preferably to choose those with similar diameters.

The bamboo culms are connected to other structural components such as foundations or beams through the end connector 16. The end connector 16 consists of two metal pieces having semicircular ring to enclose the bamboo culms, web having holes to allow the two metal pieces to be connected by bolts, flange having holes to hold face panels, and end semicircular ring having holes to attach the framework to other structural components.

The middle connector 12 is used to connect bamboo culms and face panels. The middle connector consists of two metal pieces having semicircular ring to enclose the bamboo culms, web having holes to allow the two metal pieces to be connected by bolts, and flange having holes to hold face panels.

There is an inner ring between the end/middle connector and bamboo culms to increase the contact area of the connectors. The inner ring is made of flexible materials, such as rubber. The bamboo culm is wrapped tightly by this flexible material. Besides rubber, the inner ring 14 can be made of any other materials that can be bent without fracturing, such as polyethylene, vinyl, nylon, leather, etc. Another advantage of the inner ring is that it can offset the variation of culm dimensions by either placing multiple inner rings around the culm with a smaller diameter or by tightening the flexible inner ring around the culm with a larger diameter.

In a wall, the middle connector is preferred to be placed on the top of bamboo nodes to prevent sliding. In situation where the middle connector has to be placed between two nodes, the metal strap connector 18 is used to connect two middle connectors or a middle connector and end connector to prevent sliding of the middle connectors. In a floor where sliding is not caused by gravity, the metal strap connector 18 may also be used occasionally to improve structural integrity.

In a floor, unevenly distributed force may cause rotation of the middle connector. Metal channel connector 20 and metal diagonal connector 22 are used to prevent rotation of the middle connector. The channel connector 20 is used to connect the webs of two middle connectors at the same locations. For example, as shown in FIG. 3A, they may be placed at the front (bottom) or rear (top) of the webs of two middle connectors. The diagonal connector 22 is used to connect the webs of the two middle connectors at the different locations. For example, as shown in FIG. 3A, one end of the connector 22 is placed at the front web of one middle connector and another end is placed at the rear web of the other middle connector. This arrangement is to form a triangle with the channel connector 20, diagonal connector 22, and the middle connector 12 so that the middle connector does not rotate. In a wall where unevenly distributed force is rare, the channel connector 20 and diagonal connector 22 may also be used occasionally to increase structural integrity.

Operation—FIGS. 1, 2, 3, 4

By using the connectors, this invention can be easily used to transfer load and hold face panels.

In a non-load bearing partition wall, flexible inner rings can be wrapped tightly on bamboo culms at desired locations, preferably on the top of bamboo nodes. Then the middle connectors 12 or the end connectors 18 are installed by bolting two metal pieces together at the webs. Then the end connectors are connected to other structural components such as a lumber or concrete by screws. After the framework is installed, commercial available face panels made of concrete, wood, and other materials can be attached to the flange of the middle or the end connector. Metal strap connector 18, metal channel connector 20, and metal diagonal connector 22 may be used if additional strength of the partition wall is desired.

In a load bearing wall, installation procedure is similar to non-load bearing wall except for metal strap connector 18 is more frequently used to prevent sliding. Metal channel connector 20 and metal diagonal connector 22 may also be used occasionally to further increase the integrity of the structure against strong wind or earthquake force.

In a floor, the installation procedure is similar to the previous two situations except for the metal channel connector 20 and metal diagonal connector 22 are used frequently to prevent rotation of the middle connector. The metal strap connector may be used occasionally to further increase the structural integrity.

Advantages

From the description above, a number of advantages of the framework become evident:

-   -   (a) The major component of framework is bamboo, which makes the         wall or floor using this framework lighter than walls using         other building materials. The weight reduction further causes         cost savings of other structural components such as beams,         columns, foundations, etc.     -   (b) The connectors make it possible to completely conceal bamboo         culms with panels, which improve the fire resistance of bamboo         framework, improve the aesthetics of walls or floors, and         protect the bamboo frames from adverse environment such as         excessive moisture, insects, etc.     -   (c) The hollow spaces between bamboo culms can be used to         install electrical conduits, mechanical pipes, and insulation         materials.     -   (d) Bamboo is a rapidly renewable natural material. The wide         application of the framework helps protect global environment by         reducing demand on unrenewable construction materials, energy         consumption, and harmful gas emissions.     -   (e) The inner ring used with the middle and the end connectors         provide better contact between the metal and bamboo culms. It         also facilitates the adjustment to the variation of bamboo culm         dimensions.     -   (f) No holes are drilled into bamboo culms, so the integrity of         the bamboo structure is protected.     -   (g) No wet operation is involved. The wall or floor panels can         be installed quickly and in a clean environment.     -   (h) Only five different types of metal connectors are required.

Although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of the preferred embodiments of this invention. For example, the screws used to connect the framework with support members may be replaced with anchor bolts and nuts. The bolts and nuts used to connect the framework with face panels may be replaced with screws. 

1. A method for forming bamboo framework, comprising the steps of: forming bamboo culms of equal length and close dimension; wrapping each of said bamboo culms with a flexible ring at two ends of the culm and in the middle of the culm at selected locations; joining the bamboo culms perpendicularly to a support member at spaced locations with a plurality of end connectors so as to be able to support forces acting on the culms; placing a plurality of middle connectors around said flexible rings to support face panels; joining said end connectors and middle connectors with a plurality of metal straps, diagonal connectors, and channel connectors at selected locations.
 2. A bamboo framework comprising: a plurality of bamboo culms of equal length, flexible inner rings wrapped around the two ends of said bamboo culms and in the middle of the culms at selected locations, a plurality of end connectors placed on the ends of each of the culms, a plurality of middle connectors placed around said inner rings at selected locations, a plurality of metal straps, metal diagonal connectors, and metal channel connectors at selected locations.
 3. The flexible inner ring of claim 2 wherein said is elastic and wraps tightly around the bamboo culm of claim 2 wherein said.
 4. The end connector of claim 2 wherein said comprises two metal pieces having a semicircular ring at the length of the flexible inner ring of claim 2 wherein said, two webs perpendicular to the longitudinal edges of said semicircular ring, two flanges perpendicular to said webs, an additional semicircular ring perpendicular to said semicircular ring to join support members. The lengths of the webs and the flanges are shorter than the length of the longitudinal dimension of the connector to provide spaces for end connection. The webs, the flanges and said semicircular ring to join support members have holes at selected locations.
 5. The middle connector claim 2 wherein said comprises two metal pieces having a semicircular ring at the length of the flexible inner ring of claim 2 wherein said, two webs perpendicular to the longitudinal edges of said semicircular ring, two flanges perpendicular to said webs. The webs and the flanges have holes at selected locations.
 6. The metal strap claim 2 wherein said comprises a plate metal with two holes at each end of said metal strap. Said holes are sized and spaced the same with holes in the webs claim 4 and claim 5 wherein said. The width of the metal strap is smaller than the width of the webs claim 4 and claim 5 wherein said.
 7. The diagonal metal connector claim 2 wherein said comprises a plate metal, two flanges at the end of said plate metal at the opposite direction forming an angle with the plate metal less than 90 degrees. Each of said flanges has two holes sized and spaced the same with holes in the webs claim 4 and claim 5 wherein said. The width of the diagonal metal connector is smaller than the width of the webs claim 4 and claim 5 wherein said.
 8. The channel metal connector claim 2 wherein said comprises a plate metal, two flanges at the end of said plate metal at the same direction forming an angle with the plate metal equal to 90 degrees. Each of said flanges has two holes sized and spaced the same with holes in the webs claim 4 and claim 5 wherein said. The width of the connector is smaller than the width of the webs claim 4 and claim 5 wherein said. 